// https://zhuanlan.zhihu.com/p/68185319


void adjust_ele(int arr[], int D, int length){

    int dad = D;
    for(int child=2*dad+1; child<length; ){

        child = 2*D+1;
        if(child!=length-1 && arr[child+1] > arr[child]){
            child+=1;
        }
    }



}